Scientists reported Thursday that a 4-billion-year-old meteorite from Mars caused a scattering here on Earth decades ago that contains no evidence of ancient primitive life on Mars.

In 1996, a team led by NASA announced that the organic compounds in rock It seems to have been left by living creatures. Other scientists have been skeptical, and researchers have been brushing off this hypothesis for decades, most recently a team led by the Carnegie Institution for Science. Andrew Steele.

Steele said small samples of the meteorite show that the carbon-rich compounds are actually the result of water — probably salty or brine — flowing over the rock for a long time. the findings It appears in the journal Science.

During Mars’ wet period and early past, at least two impacts occurred near the rocks, warming the planet’s surrounding surface, before a third impact bounced off the Red Planet into space millions of years ago. The 4 pound (2 kilogram) rock was found in Antarctica in 1984.

According to the researchers, groundwater moving through cracks in the rock while on Mars formed the tiny balls of carbon that are present. They said the same could happen on Earth and could help explain the presence of methane in Mars’ atmosphere.

But two of the scientists who took part in the original study disputed these latest findings, calling them “disappointing.” In a joint email, they said they are standing by Their notes in 1996.

“While the presented data gradually adds to our knowledge [the meteorite]The explanation is hardly new, and research does not support it.” Kathy Thomas Kiberta And Simon Klimt, astronomical materials researchers at NASA’s Johnson Space Center in Houston.

They added that “unsupported speculation does nothing to solve the mystery surrounding the origin of the organic matter” in the meteorite.

According to Steele, technological advances made his team’s new discoveries possible.

He praised the measurements made by the original researchers and noted that their alleged hypothesis of life “was a reasonable explanation” at the time. He and his team – which includes NASA and German and British scientists – were interested in presenting their findings “for what they are, a very exciting discovery about Mars and not a study to disprove” the original hypothesis, he said.

Steele said in an email, referring to the subterranean oceans of the moons of Saturn and Jupiter.

The only way to establish whether Mars had or still had microbial life, Steele said, is to bring samples back to Earth for analysis. NASA’s Perseverance probe on Mars has collected six samples to bring back to Earth within a decade or so; Three dozen samples are required.

After millions of years of drifting through space, the meteorite landed on an ice field in Antarctica thousands of years ago. The small, gray-green lot got its name – Allan Hills 84001 – from the hills in which it was found.

Just this week, a piece of this meteorite was used in a first-of-its-kind experiment aboard the International Space Station. Examine the microscopic scanning electron microscope of the sample. The researchers hope to use the microscope to analyze geological samples in space — on the moon one day, for example — and debris that could destroy station equipment or endanger astronauts.